Question

I have an array of people that looks like this:

$people =
    Array
    (
        [0] => Array
            (
                [email] => [e-mail]
                [name] => Name Surname
                [count] => 0
            )

        [1] => Array
            (
                [email] => [e-mail]
                [name] => Name2 Surname
                [count] => 0
            )
    )

And I have an array which is the result of a MySQL query that looks like this:

$query=
    Array
    (
        [0] => Array
            (
                [email] => [e-mail]
                [name] => Name Surname
            )

        [1] => Array
            (
                [email] => [e-mail]
                [name] => Name2 Surname
            )

        [2] => Array
            (
                [email] => [e-mail]
                [name] => Name Surname
            )

    )

For each e-mail address in $people, I’d like $people['count'] to equal how many times that e-mail address occurs in $query.

I’ve tried loads of ways to do this, and I’m not quite getting the desired result.

For the avoidance of doubt, my end result based on the example above should look like:

$people =
    Array
    (
        [0] => Array
            (
                [email] => [e-mail]
                [name] => Name Surname
                [count] => 2
            )

        [1] => Array
            (
                [email] => [e-mail]
                [name] => Name2 Surname
                [count] => 1
            )
    )

Answer 1

foreach ($people as $key => $man) { // iterating through each man
  $_occurences = 0;

  foreach ($query as $_item) // iterating through each result in the result set
    if ($_item['email'] == $man['email']) // comparing current man to each result item
      $_occurences ++;

  $people[$key]['count'] = $_occurences; // saving number of occurrences in the `count` key 

 }

---

UPD: One more solution using array_map, array_reduce and nice ternary operator. Its slower than one with foreach, but twice as compact and professional.

It is slower (in terms of performance) bec. of function calls overhead, but on “small” amount of iterations this drop is negligible. It will update $people array without reassigning it bec. we transmitted each &$man by reference.

array_map(function (&$man) use ($query) {
    $man['count'] = array_reduce($query, function ($count, $row) use ($man) {
        return ($row['email'] === $man['email']) ? ++$count : $count ;
    }, 0);
}, $people);